A survey submitted to Congress on Friday and conducted by the Pentagon found U.S. military facilities are vulnerable to extreme weather caused by climate change. The Defense Department studied climate risks to all 3,500 U.S. military sites around the world. Nearly 800 have been affected by droughts, 350 by extreme temperatures, 225 by storm surge-related flooding and more than 200 by wildfires, among other weather events.

“If extreme weather makes our critical facilities unusable or necessitate costly or manpower-intensive workarounds, that is an unacceptable impact,” according to the report. While Secretary of Defense Jim Mattis has spoken openly about the threat climate change poses to national security, President Donald Trump has mocked the link.

The Pentagon is also required under the National Defense Authorization Act passed last year to report to Congress in coming months which military sites are vulnerable to “rising sea tides, increased flooding, drought, desertification, wildfires, thawing permafrost.” The report will also address whether the military faces increased requests for disaster and humanitarian assistance.